[] Tubers, corms and bulbs, oh my!

From: Ken Mosher <ken at spatulacity.com> on 2010.02.06 at 23:42:14(20550) Thanks, Christopher. I always called them tubers but thought that they were more correctly called corms. I thought that because a botanist friend of mine said they were corms. -Ken Mosher +More Christopher Rogers wrote: > > Hiyer! > > I recently had a discussion with few Aroid Oriented Individuals about > proper terminology for the non-root, subterranean aroid parts. Or to > put it another way, do plants like Amorphophallus, Arum, > Helicodiceros, Typhonium, Colocasia, Ambrosina, and the like have > tubers, corms or bulbs? > > The answer is that they have tubers. (Or for dear Julius' sake, > "chubas"). > > A bulb is composed of thick, modified leaves, arranged in layers, for > food storage. An onion is a perfect example. > > A corm is composed entirely of stem tissue. It is literally just an > underground stem. It has an epidermal layer, a vascular cylinder with > phloem and xylem and central pith. A corm can also be a starch storage > organ, but it still has true stem tissue. This is why a corm has the > new foliage growth coming from the top and the roots coming from the > base. Corm examples are Crocus, Cyclamen and Gladiolus. A cormel is > just a diminutive corm. > > A tuber is just parenchyma (with some vascular tissue). It has an > epidermal layer with some subdermal vascular tissue, and all the rest > is parenchyma. It is almost entirely a starch storage organ. This is > why the foliage and the roots all come from the top. Most plants with > tubers have them borne on stolons, but that is not necessary. In > Amorphophallus, Arum and Typhonium for example, the stem tissue is all > encased in the small bud at the top of the tuber. That bud grows > upward into a leaf or two, and outward into roots, with the tuber > beneath. Other tuber examples are potatoes and Sinningia. > > A bulbil, in the aroid sense, is just a tuber that forms on leaves or > leaf axils. It is an unfortunate term as it obviously leads to confusion. > > I really hope that this is helpful to the Aroid community at large, > and I hope it cuts down on some of the confusion surrounding these > terms. I am sure Pete, Wilbert, Tom, Julius, The Banta or someone can > elucidate further, particularly as far as tuberous rhizomes or > rhizomatic tubers are concerned. > > Happy days, > > Christopher > > D. Christopher Rogers > > Senior Invertebrate Ecologist/ Taxonomist > > ((,///////////=======< > > branchiopod@gmail.com > > *EcoAnalysts, Inc.* > > 1.530.383.4798 > > P.O. Box 4098 > > Davis, CA 95616 > > USA > > Invertebrate Taxonomy > > Endangered Species > > Ecological Studies > > Bioassessment > > Invasive Species > > Plankton > > Phycology > > *IDAHO †¢ CALIFORNIA †¢ MISSOURI †¢ PENNSYLVANIA †¢ VANCOUVER* > > WWW.ECOANALYSTS.COM †¢ ECO@ECOANALYSTS.COM > > ------------------------------------------------------------------------ > > _______________________________________________ > Aroid-L mailing list > Aroid-L@www.gizmoworks.com > http://www.gizmoworks.com/mailman/listinfo/aroid-l > _______________________________________________ Aroid-L mailing list Aroid-L@www.gizmoworks.com http://www.gizmoworks.com/mailman/listinfo/aroid-l

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